Microelectromechanical system (MEMS) pressure sensing devices are well known. For instance, U.S. Pat. No. 4,236,137 to Kurtz et al. discloses a semiconductor pressure transducer. U.S. Pat. Nos. 5,178,016 and 6,093,579 also disclose solid state pressure sensors. U.S. Pat. No. 8,881,596 entitled, “Semiconductor Sensing Device to Minimize Thermal Noise,” owned by the Applicant of this application, discloses a MEMS pressure sensing device and is incorporated herein by reference in its entirety.
MEMS pressure sensing devices are known to “suffer” from a pressure nonlinearity or “PNL.” PNL is a function of a silicon diaphragm's deflection. The ability of a diaphragm to deflect, however, also determines a MEMS pressure sensing device's ability to detect pressure changes. As diaphragm deflection increases, so does output nonlinearity. See, for example, U.S. pre-grant publication 2015/0330856, entitled, “Pressure Sensor Device with High Sensitivity and High Accuracy,” published Nov. 19, 2015, assigned to the same Applicant and incorporated herein by reference in its entirety.
Pressure sensitivity of a MEMS pressure sensing device becomes more problematic as diaphragm size decreases. Smaller diaphragms, and smaller MEMS pressure sensing devices, however, enable manufacturing costs to be reduced for both the MEMS pressure sensing device itself and the packaging for the MEMS pressure sensing device to be placed in. An apparatus and method to shrink the die size of a MEMS pressure sensing device, while increasing sensitivity and decreasing PNL would be an improvement over the prior art.